1. Field of the Invention
This invention relates in general to devices for removing dust and other particulate contaminants from air or similar gases. More particularly, this invention relates to an air cleaner having a replaceable filter element assembly for use on internal combustion engines.
2. Description of the Prior Art
The internal combustion engine is a widely used power source which operates according to well-known principles. This type of engine is often used to power various movable vehicles, such as automobiles, trucks, snowmobiles, etc. In order for such an engine to operate properly, it is necessary to remove most of the dust, pollutants, or other particulate matter which is suspended in the air that is used as the intake air in the combustion process. Such particulate removal increases the efficiency at which the engine operates and prolongs the life of various engine components. Various types of air cleaners are used on internal combustion engines to filter the intake air.
More particularly, a special type of air cleaner is often used on the internal combustion engine of an over-the-road truck or the like. This air cleaner comprises a replaceable filter element assembly which is releasably contained inside a filter body. The filter element assembly includes two perforated spaced metal liners between which a pleated filter medium is contained. Two metal end caps integrally join the two liners and filter medium together to form a unitary filter element assembly. Whenever the pleated filter medium becomes too clogged for continued use in the filter body, it is necessary to replace the filter element assembly. This has been done in the past simply by discarding the entire filter element assembly, including the metal liners and end caps, and replacing it with an unused assembly.
The prior art structure of the filter element assembly and the prior practice of discarding the entire filter element assembly when the filter medium becomes plugged is wasteful. This is apparent since at least some of the components of the filter element assembly (e.g., the two metal liners) could be reused. Because they are not reused however, the cost of each of the filter element assemblies is increased by the need to provide two new metal liners in each one. This increases the maintenance costs for the vehicle on which such air cleaners are used. In addition, the air cleaners in commercial trucks are often replaced according to a schedule depending on the number of miles driven by the truck rather than the actual condition of the filter medium. This often means that such air cleaners are replaced before it is strictly necessary (i.e., when the filter medium has become plugged with filtered particles). Thus, the maintenance costs for vehicles using these air cleaners are further increased by the type of maintenance prevalent in the industry.
In addition, the previous filter element assemblies have been shipped from the factory in an assembled form with the filter medium being placed in the expanded form in which the medium is normally operable. Since the filter medium is often conically shaped, the fully assembled filter element assembly is usually quite large. As such these assemblies take up a great deal of space. This increases both the shipping costs and also the inventory cost of storing such filter element assemblies. In addition, because each new filter element assembly also includes two new metal liners, the weight of each assembly is also increased. This further causes an increase in shipping costs.